Three people were shot and Yoshihiro Tanbara Archivesone person is dead after a shooter opened fire at YouTube's headquarters in San Bruno, California.

Local police responded to reports of an active shooter at the company's main office Tuesday afternoon.

San Bruno Police Chief Ed Barberini said in a press conference that the suspected shooter was dead, possibly from a self-inflicted gunshot wound, and three victims had been taken to San Francisco General Hospital.

We are responding to an active shooter. Please stay away from Cherry Ave & Bay Hill Drive.

— San Bruno Police (@SanBrunoPolice) April 3, 2018

The incident began shortly before 1 p.m. PT, when a number of employees reported hearing shots from inside the building. Barberini said 911 calls began coming in at 12:46 p.m. PT and police responded within two minutes.

Active shooter at YouTube HQ. Heard shots and saw people running while at my desk. Now barricaded inside a room with coworkers.

— Vadim Lavrusik (@Lavrusik) April 3, 2018

At least one employee described hearing shouts and seeing "blood drips on the floor and stairs" inside of the company's San Bruno headquarters.

We were sitting in a meeting and then we heard people running because it was rumbling the floor. First thought was earthquake. https://t.co/gmolQmRXm1

— Todd Sherman (@tdd) April 3, 2018

I looked down and saw blood drips on the floor and stairs. Peaked around for threats and then we headed downstairs and out the front.

— Todd Sherman (@tdd) April 3, 2018

A spokesperson for SF General confirmed it had received three patients with gunshot wounds, with one in serious condition, one in critical condition, and one in fair condition.

Videos posted to Snapchat showed a heavy police presence surrounding the building and what appeared to be YouTube employees exiting with their hands raised in the air.

Spokespeople for YouTube and Google weren't immediately available, but on Twitter, Google said that it was "coordinating with authorities."

"Our Security team has been working closely with authorities to evacuate the buildings and ensure the safety of employees in the area," the company said, adding that they've advised employees to avoid the area and have opened a helpline for affected staff.

Re: YouTube situation, we are coordinating with authorities and will provide official information here from Google and YouTube as it becomes available.

— Google Communications (@Google_Comms) April 3, 2018

We continue to actively coordinate with local authorities and hospitals. Our Security team has been working closely with authorities to evacuate the buildings and ensure the safety of employees in the area.

— Google Communications (@Google_Comms) April 3, 2018

More than a thousand employees work at the San Bruno office, which is about 30 miles away from Google's Mountain View headquarters.

In addition to local police, the San Francisco Field Division of the Bureau for Alcohol, Tobacco, and Firearms said it was responding to the shooting. CBS also reported officials from Homeland Security at the scene. President Donald Trump has also been briefed, he said on Twitter.

.@SecNielsen has been briefed on the ongoing situation in San Bruno, CA. @DHSgov will support state and local officials in any way we can.

— Tyler Q. Houlton (@SpoxDHS) April 3, 2018

Was just briefed on the shooting at YouTube’s HQ in San Bruno, California. Our thoughts and prayers are with everybody involved. Thank you to our phenomenal Law Enforcement Officers and First Responders that are currently on the scene.

— Donald J. Trump (@realDonaldTrump) April 3, 2018

Additional reporting by Kerry Flynn